Interlocking electromagnetic relay structures



March 4, 1958 A; LAUTERER INTERLOCKING ELECTROMAGNETIC RELAY STRUCTURES Filed Sept. 2, 1955 Fla! FIG

INVENTOR ANTON LAU RER ATTORNEY United States PatentO 1 INTERLOCKING ELECTROMAGNETIC RELAY STRUCTURES Anton Lauterer, Stuttgart, Germany, assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application September 2, 1955, Serial No. 532,331 Claims priority, application Germany September 11, 1954 4 Claims. (Cl. 74-483) My invention relates to interlocking or stick and latch electromagnetic relay structures consisting of two relay systems, the armatures of which are coupled. In such structures, upon the attraction of either one of the armatures, the other one will be dropped oif, provided its respective relay coil is deenergized, and the attracted armature will be latched in its actuated position so that the contacts associated with this armature will remain in the operatedposition even after the relay system associated with that armature has become deenergized. By this means there may, under certain circumstances, be achieved a considerable saving of current which in many cases is of great advantage and accounts for the increasing use of interlocking or stick and latch relays.

In prior arrangements of this kind the coupling between the armatures of the respective relay systems has been effected by means of control levers which are hinged to the armatures and which are rotatable about fixed centers of rotation. Such arrangements, however, have the dis advantage that the ends of the control levers slide over one another during the movement of attraction of one armature, whereby the attraction power is partially consumed in overcoming the friction produced between the two control levers and this friction becomes greater the more the armatures are loaded with Contact set assemblies. The striking current of the relay systems is limited by the ampere turns of the windings and under certain conditions and with high loading of the armatures may be easily ex ceeded to an unsafe extent.

It has already been proposed to diminish the abovementioned undesired friction between the control levers by providing the relay systems with an operating time delay so that upon the attraction of one armature the other will remain attracted for a short period and will then drop off without engaging the other control lever. This, however, requires special circuitry and limits the practical applications in which stick and latch relays may be employed.

It is an object of the present invention to overcome the above disadvantages in a structural manner whereby interlocking relays may be used in numerous circuit arrangements in which it is not convenient or possible to provide operating time delays.

According to the invention the undesired friction between the armature connecting links is greatly reduced by providing separate locking levers in addition to the control levers which are actuated by the respective armatures, such locking levers being actuated by the associated control levers and serving to latch the respective other control lever. The locking levers are rotated by the associated control levers by means of shoulders provided on the latter, the arrangement being such that these shoulders engage the control lever during only a small part of the travel of the control lever thus reducing the frictional resistance.

The control levers are connected to the respective armatures by means of connecting links which are secured at one end to the respective armature and at the other end are embraced by fork-like extensions of the control levers. In certain types of security systems, for example, in railroad signaling, it is necessary to insure that in the event of any failure of the latching devices of interlocking relays, that the two armatures can never occupy their dropped positions at the same time. This requirement is met in accordance with a further feature of my invention by providing a further lever fulcrumed on a centrally located pivot and so arranged that the ends of the connecting links remote from the respective armatures rest upon the two ends of such further lever so as to prevent both relay armatures from dropping off at the same time.

The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood, by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Fig. 1 is a partly diagrammatic front view of the interlocking structure utilizing my invention; and

Fig. 2 is an end view of one of the pair of locking levers used in the showing of Fig. 1.

Reference will first be made to Fig. l in which only sufficient of two relay systems is illustrated for the purpose of explaining the invention. Armatures 1a and 11) control the respective contact sets 2a and 2b in any known manner (as indicated by the broken lines) and are arranged to be attracted by the energization of relay windings 3a and 3b. The armatures 1a and lb are coupled by connecting links 4a and 4b to two-armed control levers 5a and 5b pivotally mounted on fixed pivots 6a and 6b. Single-armed locking levers 7a and 7b are also respectively mounted on pivots 6a and 6!) but their free ends extend outwardly further than do the free ends of the control levers 5a, 5b. The locking levers 7a and 7b are bent so as to cross the control levers 5a and 5b, as shown in Fig. l, and the control levers 5a and 5b are provided with shoulders 8a, 8b and 9a, 9b for actuating the locking levers 7a and 7b. The locking levers 7a and 7b have an end profile similar to that shown in Fig. 2, there being outwardly extending portions 10b and 1111 which cooperate with shoulders 8b and 9b. The profile of the locking lever 7a is a mirror image of the lever 7b and is provided with outwardly extending portions 10a and 11a, respectively, which portions cooperate with the shoulders and 9a, respectively. The locking levers 7a, 7b are provided with apertures such as 12!) in Fig. 2 through which the pivot 622 may pass. It will be understood that locking lever 7a is provided with a similar aperture.

In the drawing, the right-hand relay system is shown as attracted and latched, while the left-hand system is dropped off, the control lever 5b of the right-hand system having been latched by the locking lever 7a of the lefthand system in the preceding operation. Assume now that the winding 3a of the left-hand system is energized and the armature 1a attracted. Through the intermediary of the connecting link 4a, the left-hand end of the control lever 5a will be lifted and the right-hand end of that lever will clear the top surface of lever 5b and be depressed. In the last part of the movement of control lever 5a, the shoulder 9a will engage the locking lever 7a and thereby remove the latch from the control lever 5b of the other relay system. The momentary friction thereby generated can be tolerated without objection because the armature 111 has approached the end of its movement and is near to the core of the winding 3a, in which position the electric flux is strongest and consequently the attractive power of the relay is nearing its maximum. When the control lever 51) is unlatched, its left-hand end will lift and its right-hand end will be lowered due to the weight of the armature lb or to the spring action of the contacts.

In the last portion of this movement, the shoulder 8b on the control lever 5b will lift the locking lever 7b and position it below the right-hand end of the control lever 5a of the left-hand relay system. Thus the armature 1a is now in its attracted and latched position, Whilst the armature 1b is dropped off.

While I have described above the principles of my invention in connection With specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of my invention.

What is claimed is:

1. An arrangement for the mutual interlock of the armatures of two electromagnetic relays, each relay comprising a control lever, a locking lever and means to couple said control lever to the relay armature for actuation thereby, a pair of spaced, fixed pivots disposed intermediate said relays, each control lever fulcrumed on one of said fixed pivots adjacent its associated relay at a point intermediate the ends of said lever, each locking lever having an end pivotally mounted on the same fixed pivot as its associated control lever and having its other end adjacent an end of the control lever associated with the other relay, means for selectively setting each of said locking levers into locking relation with the control lever of the other relay and means for releasing a set locking lever, said setting and releasing means comprising separate lost-motion means between each locking lever and its associated control lever, whereby a set locking lever is adapted to be released upon the attainment by its associated control lever of a predetermined angular position about its pivot upon operation of the associated armature and whereby the unset locking lever is adapted to be set upon the attainment by its associated control lever of a predetermined angular position about its pivot upon the release of its associated armature.

2. An arrangement as claimed in claim 1, wherein each of said control levers is shaped in the form of an obtuse angle and said fulcrum point is at the point of intersection of the sides thereof, said control levers mounted in reversed position with respect to each other.

3. An arrangement as claimed in claim 2, wherein each of said locking levers has a length greater than the length of a side of its associated control lever.

4. An arrangement as claimed in claim 3, wherein said lost-motion means comprises a pair of shoulders on each of said control levers extending outwardly .from opposite edges of a side thereof intermediate the ends thereof, and a reverse bend in said locking levers each portion of the bend adapted to be acted upon by a different shoulder of said pair only in the last portion of the angular rotation of the respective control lever.

References Cited in the file of this'patent UNITED STATES PATENTS 948,583 Barnes Feb. 8, 1910 2,419,258 Field Apr. 22, 1947 2,604,796 Freese July 29, 1952 2,610,274 Kelleigh Sept. 9, 1952 FOREIGN PATENTS 173,922 Great Britain Jan. 19, 1922 135,011 Sweden Mar. 26, 1952 

